A5075742308- Additive Manufacturing and 3D Printing Technologies
- Metal Alloys Wear and Properties
- Additive Manufacturing Materials and Processes
- Non-Destructive Testing Techniques
- Manufacturing Process and Optimization
- Recycling and utilization of industrial and municipal waste in materials production
- Corrosion Behavior and Inhibition
- Pigment Synthesis and Properties
- Hydrogen embrittlement and corrosion behaviors in metals
- Metal and Thin Film Mechanics
- High-Velocity Impact and Material Behavior
- Power Transformer Diagnostics and Insulation
- Microstructure and Mechanical Properties of Steels
- Mineral Processing and Grinding
- Advanced machining processes and optimization
- Mechanical Failure Analysis and Simulation
- Microstructure and mechanical properties
- Mechanical stress and fatigue analysis
- Industrial Vision Systems and Defect Detection
- Asphalt Pavement Performance Evaluation
- Natural Fiber Reinforced Composites
- Concrete and Cement Materials Research
- Software Reliability and Analysis Research
- Polymer Science and PVC
- Diamond and Carbon-based Materials Research
Universidad Nacional de Colombia
2001-2025
Cenim - Centro Nacional de Investigaciones Metalurgicas
2009
Karlsruhe University of Education
1986
This study investigated the effects of multiple selective laser sintering (SLS) cycles on a polyamide 12 powder blend comprising 70% recycled and 30% virgin material. Thermal analysis revealed significant changes in thermal behavior powder, including an increase melting temperature crystallinity decrease crystallization temperature. Particle size distribution statistically differences between initial post states. Microscopic observations strong correlation crystal particle morphologies....
This study investigated the effects of multiple laser sintering (LS) cycles on a polyamide 12 powder mixture 70% recycled material and 30% virgin polymer. research aimed to understand how repeated LS processing influences this specific mixture's thermal structural properties, which is crucial for optimising its performance in additive manufacturing applications. A analysis revealed significant changes behaviour over successive build cycles. Specifically, there was an observed increase both...
Abstract The wall thickness and build direction of PA 12 parts manufactured via SLS are currently being investigated for applications requiring low weight good mechanical properties (ultimate tensile strength, elongation at break, elastic modulus, hardness). Current design guidelines the process include recommendations about influence on part; however, recommended minimum only considers process's manufacturability, so this study aims to determine orientation conditions that present slightest...
In the first field trial with synthetic malaria vaccine SPf66 in a large population naturally exposed to malaria, 9957 persons > 1 year old and residing on Colombian Pacific coast received three doses of vaccine. To evaluate safety, clinical observations were made 30 min 48 h after each immunization. There no adverse reactions 95.7% cases. 4.3% cases reactions, local induration erythema most frequent. randomly selected group vaccinees, anti-SPf66 antibody titers measured third dose: 93%...
Purpose This paper aims to investigate and explain the dual fracture behaviour of PA12 specimens sintered by selective laser sintering (SLS) as a function wall thickness build direction with powder mixture 30:70. To achieve this objective, research related chemical, thermal structural behaviours input variables was carried out describe why ductile-fragile occurs during fractures under uniaxial tension manufactured via methodology material analysis manufacturing processes....
The influence of Martensite Volume Fraction (MVF) on fracture mechanisms in a Dual Phase steel with two different grain sizes was studied this work.Ferrite-Martensite microstructure obtained by an intercritical heat treatment for both groups sizes.The results show direct relationship between higher temperature during the and increase MVF.The fine MVF presents high tensile strength good ductility.Furthermore, relation to material behavior under impact conditions, refinement values promote...
Failure analysis aims at collecting information about how and why a failure is produced. The first step in this process visual inspection on the flaw surface that will reveal features, marks, texture, which characterize each type of fracture. This generally carried out by personnel with no experience usually lack knowledge to do it. paper proposes classification method for three kinds fractures crystalline materials: brittle, fatigue, ductile. uses 3D vision, it expected support analysis....
The influence of Martensite Volume Fraction (MVF) on fracture mechanisms in a Dual Phase steel with two different grain sizes was studied this work.Ferrite-Martensite microstructure obtained by an intercritical heat treatment for both groups sizes.The results show direct relationship between higher temperature during the and increase MVF.The fine MVF presents high tensile strength good ductility.Furthermore, relation to material behavior under impact conditions, refinement values promote...
A study on the effect of vacuum assisted resin transfer moulding (VARTM) manufacturing process mechanical properties cotton/epoxy composite is presented in this investigation. Woven cotton was used as reinforcing material embedded epoxy resin. The woven treated with sodium hydroxide for one hour at concentrations 0% to 20%. tensile test showed that untreated had highest ultimate strength and Young’s modulus. Observation fracture surface by scan electronic microscopy (SEM) compared hand...
This study aimed to scale the process of encapsulation in clay heavy metals Ni, Cr, and Cu, traditionally carried out at laboratory level, up industrial conditions. For this purpose, sludge from galvanic industry, considered highly polluting, was mixed with used make traditional ceramics. The concentrations were 2%, 5%, 8% by weight. Two shaping processes ceramic industry used: extrusion dry pressing, sintering gas kilns 2 firing cycles: fast, lasting 34 min a roller kiln, slow, 42 h tunnel...
En la reconstrucción de piezas maquinarias es esencial determinar mejor opción en cuanto a material depositado por soldadura para recuperación geometrías perdidas se refiere. El presente trabajo desarrolló mejorar las aplicaciones recubrimientos duros y materiales relleno “sprockets”, pero que pueda extrapolar al uso industrias diferente tipo. Se tomaron cuenta dos (2) factores, temperatura aplicación, afectan características finales los aplicados soldadura. Los resultados obtenidos...
The research calculates the rolling process conditions in a 3-roll bending machine. Initially, structure and mechanical properties of highstrength steel to be processed are determined an experimental manner. Then, equations that allow determining relationship between thickness width bent established, taking into consideration strength features Finally, some graphs help achieving efficient adequate processing presented, choosing width/height required for plate forming, according its...
En el presente trabajo se describe la morfología y formación de los tipos cráteres obtenidos, en impacto proyectiles 5,56 SS109, sobre siete chapas acero AISI-SAE 1045 que fueron sometidas a diferentes tratamientos térmicos, comparando tipo estructuras deformación fractura obtenidas con las formadas por uno estos una chapa comercial para blindaje. Cada caracterizó mediante ensayos inspección visual metalografía evaluándose, partir resultados, papel ejerce microestructura obtenida nivel...
Abstract A case study of the failure analysis a PVC drinking water pipeline is presented. One week after installation in construction zone building, longitudinal cracking, and pressure drop occurred an underground pipeline, investigation was carried out to determine causes event. Based on results visual inspection, dimensional metrology, plastography, microhardness, fractography, FTIR analysis, stress mechanisms pipe were identified as creep slow crack growth. The cause development these...
The National University of Colombia’s Engineering School’s AFIS research group has helped several public and private institutions during the last five years in analysing causes failures presented elevation transport machinery leading to expensive consequences even loss life. A typical wire rope failure modes have been identified, along with their common causes. These are this work offer help our industry’s engineers technicians, allowing them identify possible risk situations routine...
In an aquatubular steam boiler belonging to electric power plant, a recurrent cracking phenomenon was presented in tubes of the generator vapor area elbows around peepholes furnace boiler, that it caused lost and maintenance stops not programmed. To find cause problem they were analyzed laboratory series failed other retired similar areas being carried out studies chemical composition, metalography, fractography EDS microanalysis on obtained samples. The failure mechanism SCC from pitting...